content: /*
   * Copyright 2017 David Karnok
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package hu.akarnokd.reactive4javaflow.impl.schedulers;
  
  import hu.akarnokd.reactive4javaflow.*;
  import hu.akarnokd.reactive4javaflow.functionals.AutoDisposable;
  import hu.akarnokd.reactive4javaflow.impl.*;
  
  import java.lang.invoke.*;
  import java.util.concurrent.TimeUnit;
  
  public final class PeriodicTask implements Runnable, AutoDisposable {
  
      final SchedulerService.Worker worker;
  
      final Runnable actual;
  
      final long period;
  
      final TimeUnit unit;
  
      final long start;
  
      long count;
  
      AutoDisposable first;
      static final VarHandle FIRST = VH.find(MethodHandles.lookup(), PeriodicTask.class, "first", AutoDisposable.class);
  
      AutoDisposable next;
      static final VarHandle NEXT = VH.find(MethodHandles.lookup(), PeriodicTask.class, "next", AutoDisposable.class);
  
      public PeriodicTask(SchedulerService.Worker worker, Runnable actual, long period, TimeUnit unit, long start) {
          this.worker = worker;
          this.actual = actual;
          this.period = period;
          this.unit = unit;
          this.start = start;
      }
  
  
      @Override
      public void run() {
          try {
              actual.run();
          } catch (Throwable ex) {
              FolyamPlugins.onError(ex);
              return;
          }
  
          SchedulerService.Worker w = this.worker;
  
          long time = start + (++count) * period;
          long now = w.now(unit);
          long delay = Math.max(0L, time - now);
  
          AutoDisposable d = w.schedule(this, delay, unit);
          DisposableHelper.replace(this, NEXT, d);
      }
  
      @Override
      public void close() {
          DisposableHelper.close(this, FIRST);
          DisposableHelper.close(this, NEXT);
      }
  
      public void setFirst(AutoDisposable d) {
          DisposableHelper.replace(this, FIRST, d);
      }
  }
  